CoChat
Sign Up
Cited by 117Planetary Science and ExplorationAstro and Planetary ScienceGeological and Geochemical Analysis

Comprehensive imaging and Raman spectroscopy of carbonate globules from Martian meteorite ALH 84001 and a terrestrial analogue from Svalbard

Open access
Steele, A., Fries, M. D., Amundsen, H. E. F., Mysen, B. O., Fogel, M. L., Schweizer, M., Boctor, N. Z.·2007·Meteoritics & Planetary Science
DOI 10.1111/j.1945-5100.2007.tb00590.x
Open this paper in CoChat — free accountOpen PDF

Abstract

Abstract— We report a comprehensive imaging study including confocal microRaman spectroscopy, scanning electron microscopy (SEM), and 3‐D extended focal imaging light microscopy of carbonate globules throughout a depth profile of the Martian meteorite Allan Hills (ALH) 84001 and similar objects in mantle peridotite xenoliths from the Bockfjorden volcanic complex (BVC), Svalbard. Carbonate and iron oxide zoning in ALH 84001 is similar to that seen in BVC globules. Hematite appears to be present in all ALH 84001 carbonate‐bearing assemblages except within a magnesite outer rim found in some globules. Macromolecular carbon (MMC) was found in intimate association with magnetite in both ALH 84001 and BVC carbonates. The MMC synthesis mechanism appears similar to established reactions within the Fe‐C‐O system. By inference to a terrestrial analogue of mantle origin (BVC), these results appear to represent the first measurements of the products of an abiotic MMC synthesis mechanism in Martian samples. Furthermore, the ubiquitous but heterogeneous distribution of hematite throughout carbonate globules in ALH 84001 may be partly responsible for some of the wide range in measured oxygen isotopes reported in previous studies. Using BVC carbonates as a suitable analogue, we postulate that a low temperature hydrothermal model of ALH 84001 globule formation is most likely, although alteration (decarbonation) of a subset of globules possibly occurred during a later impact event.

Integrity signals

Registry

Crossref · 10.1111/j.1945-5100.2007.tb00590.x

Cites

55 of 55 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

4 of 53 cited sources checked · 2 supported · 1 flagged · accuracy not yet measured

  • Findingown data

    Carbonate deposition post-dates glass formation.

    “a thin film of carbonate was layered over the glass, revealing that carbonate deposition post-dates glass formation”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Corrigan and Harvey (2004) source

      The Feldspathic Glass section (p. 10) says feldspathic glass was the last phase to enter the fractures and that the carbonates beside it were mechanically entrained, not precipitated after glass intrusion. It also says the stratigraphy is inconsistent with glass formation preceding the carbonate MSM sequences. The paper therefore does not interpret carbonate on the glass as evidence of later deposition. (LLM, conf=0.88)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured
  • Premisecitation

    BVC carbonate globules formed from a single event during the eruption of Sverrefjell volcano about 1 Myr ago.

    “to have formed from a single event during the time of the eruption of Sverrefjell volcano about 1 Myr ago.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Corrigan and Harvey (2004) source

      The Introduction (p. 2) discusses ancient carbonates in the martian meteorite ALH 84001, not BVC carbonate globules. Searches for BVC, Sverrefjell, and a formation event about 1 Myr ago found no passage addressing the attributed claim; the paper's account of different carbonates does not contradict it. (LLM, conf=0.78)

      Experimental — accuracy not yet measured
  • Interpretationcitation

    The globules in ALH 84001 also formed from a single event.

    “which adds weight to the argument that the globules in ALH 84001 also formed from a single event.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Corrigan and Harvey (2004) source
  • Findingown data

    BVC xenolith carbonates were predominately white throughout with darkened centers and rims.

    “In comparison, the BVC xenolith carbonates were predominately white throughout with darkened centers and rims.”
    Quote in the paperNot a substantial claim
  • Findingown data

    Hematite is present in all ALH 84001 carbonate-bearing assemblages except within a magnesite outer rim found in some globules.

    “Hematite appears to be present in all ALH 84001 carbonate-bearing assemblages except within a magnesite outer rim found in some globules.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim. 28
  • May combine two claims. 38
  • The quote only partly states this claim. 2

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    This possibly explains the observations of Corrigan and Harvey (2004) that high-temperature interactions between carbonate and glass were not apparent in the samples they studied.

    “This possibly explains the observations of Corrigan and Harvey (2004) that high-temperature interactions between carbonate and glass were not apparent in the samples they studied, as opposed to other studies (e.g., Barber and Scott 2003).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Corrigan and Harvey (2004) source

  • May combine two claims.

    Findingown data

    The peak center distribution of the ~300 and ~1090 cm-1 bands indicates four distinct zones in ALH 84001 and only two zones in BVC carbonates.

    “From Raman spectra of the carbonate standards, the peak center distribution of both the ~300 and ~1090 cm -1 bands of ALH 84001 and BVC carbonates indicates four distinct zones in ALH 84001 (labeled a-d in Figs.3b and 3d).There are only two zones measured in the BVC carbonates (labeled 1 and 2 in Figs.3b and 3d).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Zone 2 of the BVC samples is almost pure magnesite and appears marginally less iron-rich than the magnesium carbonates from the outer rims of ALH 84001.

    “Zone 2 of the BVC samples is almost pure magnesite and appears marginally less iron-rich than the magnesium carbonates from the outer rims of ALH 84001 (ALH 84001-D).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    In BVC globules, carbon spectra were indicative of mainly amorphous macromolecular material that was found spatially associated with rings of magnetite at both the center and periphery of the globule.

    “The carbon spectra were indicative of mainly amorphous macromolecular material (Fig. 5) that was found spatially associated with rings of magnetite at both the center and periphery of the globule.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingcitation

    Most ALH 84001 globules had only a single magnetite rim, whereas some contained a white magnesite zone between two outer rims of magnetite.

    “Whereas some globules contained a white magnesite zone between two outer rims of magnetite-as identified from previous observations (McKay et al. 1996) and during Raman mapping-most had only a single magnetite rim”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites McKay et al. 1996 source

  • May combine two claims.

    Findingown data

    Abrading the surface of ALH 84001 globules showed a transition from orange carbonate at the surface to white carbonate beneath, and the white carbonate contained small veins and concentrations of reddish material.

    “Abrading the surface of globules from ALH 84001 with a cleaned stainless steel needle showed a transition from the orange carbonate at the surface to a white carbonate beneath.This white carbonate contained small veins and concentrations of a reddish material”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The vast majority of MMC found in ALH 84001 is relatively amorphous, with crystalline graphite occurring in two localities among the matrix magnetite assemblages analyzed.

    “The vast majority of MMC found in ALH 84001 is relatively amorphous, with crystalline graphite occurring in two localities among the matrix magnetite assemblages analyzed.”
    Quote in the paperNot a substantial claim

  • May combine two claims. The quote only partly states this claim.

    Findingnone given

    Laser heating visibly damaged freshly revealed surfaces only after the laser power was increased above 10 mW, an intensity significantly greater than the 0.3-1 mW used in this study.

    “Laser heating visibly damaged freshly revealed surfaces only after the laser power was increased above 10 mW”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingnone given

    The zoning pattern in BVC globules is spatially much finer than in ALH 84001, and oscillates between these two end members before magnetite deposition begins at the outer rim.

    “The zoning pattern in BVC globules, however, is spatially much finer than in ALH 84001, and oscillates between these two end members before magnetite deposition begins at the outer rim.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    In ALH 84001 globule assemblages, hematite and pyrrhotite were distributed heterogeneously throughout the globules, whereas magnetite was concentrated mostly within the rims and as discrete 0.5-5 μm patches within the carbonate globules.

    “Whereas hematite and pyrrhotite were distributed heterogeneously throughout the globules, magnetite was concentrated mostly within the rims and as discrete 0.5-5 μm patches within the carbonate globules.”
    Quote in the paperSubstantial claim

  • The quote only partly states this claim.

    Findingown data

    Complex zonation is seen in slab carbonates that is similar to variation observed proximal to magnetite in the globules.

    “Complex zonation is also seen in these”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The characteristic ~180 cm-1 peak of calcite was not detected in this study, suggesting that the calcium is present within a sideritic carbonate, possibly as ankerite.

    “However the characteristic ~180 cm -1 peak of calcite was not detected in this study, suggesting that the calcium is present within a sideritic carbonate, possibly as ankerite.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The type 3 'ghost' globules appear alongside intact carbonate globules, indicating that the spatial distribution of any heating event was heterogeneous on the scale of tens of microns.

    “Interestingly, they appear alongside intact carbonate globules (Fig. 1a), indicating that the spatial distribution of any heating event was heterogeneous on the scale of tens of microns.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    An outer 'crust' in the ALH 84001 carbonate globules is orange and that below this layer the carbonate is white with a red/pink coloration.

    “An outer”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given

    Our observations are consistent throughout the entire depth profile of ALH 84001.

    “Our observations are consistent throughout the entire depth profile of ALH 84001.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    ALH 84001 carbonates exhibit four distinct zones in the peak center shift of the carbonate 330 cm-1 peak, and BVC carbonates exhibit two distinct zones.

    “The peak center shift of the carbonate 330 cm -1 peak showing four distinct zones, marked by the letters a-d.”
    • Also stated in: § IMPLICATIONS OF THIS WORK · plain
      “ALH 84001 is shown in red and exhibits four distinct peaks indicative of the zones seen in (b); BVC is in blue and shows two distinct peaks correlating to the areas marked in (d).”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    Raman spot spectra were collected for known compounds to assist in assignment of the Raman bands observed in ALH 84001 and BVC carbonates.

    “Raman spot spectra were collected for a number of known compounds to assist in assignment of the Raman bands observed in ALH 84001 and BVC carbonates.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    The laser heating experiment was also conducted on the siderite reference material to ensure that laser heating was not responsible for the observations of hematite in the ALH 84001 carbonates.

    “The experiment was also conducted on the siderite reference material to ensure that laser heating was not responsible for the observations of hematite in the ALH 84001 carbonates.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    A cosmic ray reduction routine was used to reduce the effects of stray radiation on Raman images, as was image thresholding to reject isolated bright pixels.

    “A cosmic ray reduction routine was used to reduce the effects of stray radiation on Raman images, as was image thresholding to reject isolated bright pixels.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    A range of carbonate globules in BVC xenoliths occur both as trapped inclusions within mantle minerals and in pockets between mineral grains, and are interpreted to have been deposited by primary mantle fluids.

    “a range of carbonate globules in BVC xenoliths occur both as trapped inclusions within mantle minerals and in pockets between mineral grains, and are interpreted to have been deposited by primary mantle fluids (Amundsen 1987).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Amundsen 1987 source

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    Alteration (decarbonation) of a subset of ALH 84001 globules possibly occurred during a later impact event.

    “although alteration (decarbonation) of a subset of globules possibly occurred during a later impact event.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    The BVC eruptive centers have a range of different carbonate deposits, including magnesite globules similar to those found in ALH 84001.

    “The BVC eruptive centers have a range of different carbonate deposits (Amundsen 1987), including magnesite globules similar to those found in ALH 84001.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Amundsen 1987 source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    Fluorescence effects were inhibited by the use of specific peak fitting in place of spectral area sums and by the confocal optics used in this instrument.

    “Fluorescence effects were inhibited by the use of specific peak fitting in place of spectral area sums and by the confocal optics used in this instrument.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    A study to incrementally increase the laser power during analysis was conducted to ensure that the laser power used was not affecting the samples.

    “Therefore, to ensure that the laser power used was not affecting the samples, a study to incrementally increase the laser power during analysis was conducted.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    Hot CO2-containing aqueous fluids cooled rapidly, during which time the oxygen fugacity fell, thus promoting the formation of reduced-carbon phases alongside magnetite.

    “Hot CO 2 -containing aqueous fluids cooled rapidly, during which time the oxygen fugacity fell, thus promoting the formation of reduced-carbon phases alongside magnetite.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: The system was buffered by hematite and magnetite as temperature decreased.

  • May combine two claims.

    Interpretationreasoning

    The MMC in ALH 84001-1 is more graphitic in nature than that in ALH 84001-2, illustrating there is a range of MMC in ALH 84001 tending from very amorphous to more graphitic.

    “Coupling this observation with the presence of a second order carbon peak appears to confirm that the MMC in ALH 84001-1 is more graphitic in nature than that in ALH 84001-2, thus illustrating there is a range of MMC in ALH 84001 tending from very amorphous to more graphitic.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    Both ALH 84001 and BVC globules appear to be slightly recessed into the host mineral, suggesting that some interaction between the host rock and the globules took place during their formation.

    “Both the ALH 84001 and BVC globules appear to be slightly recessed into the host mineral (seen in Fig. 1c).This suggests that some interaction between the host rock and the globules took place during their formation.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Graphite has been previously detected by Raman spectroscopy in the Martian meteorite NWA 1068.

    “Graphite has been previously detected by Raman spectroscopy in the Martian meteorite NWA 1068 (Hochleitner 2004).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Hochleitner 2004

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Becker et al. (1999) demonstrated the presence of MMC in the matrix of ALH 84001.

    “Becker et al. (1999) demonstrated the presence of MMC in the matrix of ALH 84001.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Becker et al. 1999 source

  • May combine two claims.

    Interpretationreasoning

    The siderite originally contained in these magnetite rings was removed by either dissolution or vaporization.

    “We are, therefore, left with the observation that the siderite originally contained in these magnetite rings was removed by either dissolution or vaporization.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    The BVC globule samples are known to have formed from a single event during the time of the eruption of Sverrefjell volcano about 1 Myr ago.

    “Conversely, the BVC globule samples are known to have formed from a single event during the time of the eruption of Sverrefjell volcano about 1 Myr ago.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    During this process, the conditions in BVC samples evidently entered the magnetite/graphite stability field twice, as MMC carbon with magnetite is detected in both the center and the outer rims of the carbonate globules.

    “During this process, the conditions in BVC samples evidently entered the magnetite/graphite stability field twice, as MMC carbon with magnetite is detected in both the center and the outer rims of the carbonate globules.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: The system was buffered by hematite and magnetite as temperature decreased.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Thermodynamic calculations and experimental data on the thermal breakdown of siderite show that PAHs, graphite, and MMC are produced.

    “Thermodynamic calculations and experimental data on the thermal breakdown of siderite show that PAHs, graphite, and MMC are produced”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Koziol 2001

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites McCollom 2003 source
    • cites Treiman 2003 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Flynn et al. (1999 and 2000) showed the presence of C-C, C=C, and possibly C-H bonds in both carbonate and rim material.

    “Flynn et al. (1999 and2000) showed the presence of C-C, C=C, and possibly C-H bonds in both carbonate and rim material (Becker et al. 1999;Flynn et al. 1998;Flynn et al. 1997).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Flynn et al. 1999

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Flynn et al. 2000

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Study design and conductown data

    No visible damage to any surface or change in Raman spectra was observed using 0.3-1 mW and 5 s integration times.

    “No visible damage to any surface or change in Raman spectra was observed using 0.3-1 mW and 5 s integration times.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationcitation

    Any secondary heating event above 40-80 °C should have destroyed the magnetic properties of primary deposited magnetites and pyrrhotites in all globule types, unless the magnetite and pyrrhotite in the outer rim of type 2 globules and the magnetite within the matrix were formed in this event.

    “Any secondary heating event above 40-80 °C (Weiss et al. 2000) should have destroyed the magnetic properties of primary deposited magnetites and pyrrhotites in all globule types, unless the magnetite and pyrrhotite in the outer rim of type 2 globules and the magnetite within the matrix were formed in this event.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Weiss et al. 2000 source

  • May combine two claims.

    Interpretationnone given

    The MMC associated with BVC globules was deposited at the same time a CO2- and Fe-rich mantle-derived fluid deposited magnetite, hematite, and carbonate as a single event without the influence of biology.

    “The MMC associated with these globules was deposited at the same time a CO 2and Fe-rich mantle-derived fluid deposited magnetite, hematite, and carbonate as a single event without the influence of biology.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    Our data are consistent with the arguments that carbonate globules in ALH 84001 formed from rapidly cooling hydrothermal Fe- and CO2-rich fluids, principally due to their chemical and textural similarity to BVC carbonates.

    “Our data are consistent with the arguments that carbonate globules in ALH 84001 formed from rapidly cooling hydrothermal Fe-and CO 2 -rich fluids, principally due to their chemical and textural similarity to BVC carbonates.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Brearley (2003) proposed that during this heating event, the meteorite was experiencing considerable thermal heterogeneity.

    “Concomitant to the shock event, Brearley (2003) proposed that during this heating event, the meteorite was experiencing considerable thermal heterogeneity, a factor expanded upon by Treiman (2003).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Brearley 2003 source
    • cites Treiman 2003 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Brearley (2003) speculated that fracturing of the magnetite rim matrix boundary is evidence of a volume decrease associated with magnetite formation from siderite during a shock event.

    “Brearley (2003) speculated that fracturing of the magnetite rim matrix boundary is evidence of a volume decrease associated with magnetite formation from siderite during a shock event.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Brearley 2003 source

  • May combine two claims.

    Premisecitation

    Evidence from remnant magnetism in the magnetite and pyrrhotite of the globules, combined with petrographic studies of plagioclase grains, indicates that this meteorite has not been exposed to a temperature above 40 °C or a change in bulk rock temperature of more than 120 °C.

    “Evidence from remnant magnetism in the magnetite and pyrrhotite of the globules, combined with petrographic studies of plagioclase grains, however, indicates that this meteorite has not been exposed to a temperature above 40 °C or a change in bulk rock temperature of more than 120 °C (Fritz et al. 2005;Weiss et al. 2000;Weiss et al. 2002).”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Fritz et al. 2005 source
    • cites Weiss et al. 2000 source
    • cites Weiss et al. 2002 source

  • May combine two claims.

    Interpretationreasoning

    Carbonate globules may form from fluids that vary greatly in their initial temperatures, though they may not vary much in the temperature at which deposition of the carbonate occurs.

    “This indicates that carbonate globules may form from fluids that vary greatly in their initial temperatures, though they may not vary much in the temperature at which deposition of the carbonate occurs.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing).

    Premisecitation

    The outer rim of dual rim globules was formed by thermal decomposition of siderite during a shock event to leave magnesite and magnetite.

    “It has also been suggested that the outer rim of dual rim globules was formed by thermal decomposition of siderite during a shock event to leave magnesite and magnetite”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Barber and Scott 2003 source
    • cites Barber et al. 2001

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Scott et al. 2002

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation

    The observed petrography may only reflect the last impact event, as previous impact event textures would be reset.

    “Therefore the observed petrography may only reflect the last impact event, as previous impact event textures would be reset (Fritz 2006, personal communication).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Fritz 2006, personal communication

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    The sulfur-containing mineral pyrrhotite found in the rims of globules has also been suggested to form from decomposition of pyrite during a thermal event after primary precipitation, and thus both type 1 and 2 globules may have experienced some transient heating event.

    “The sulfur-containing mineral pyrrhotite found in the rims of globules (Figs.6c and 7e) has also been suggested to form from decomposition of pyrite during a thermal event after primary precipitation, and thus both type 1 and 2 globules may have experienced some transient heating event (Golden et al. 2004a).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Golden et al. 2004a

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Interpretationreasoning

    Hydrogen would be present in this system from dissociation of water and perhaps linked to dissolution of the host mineral matrix.

    “Hydrogen would be present in this system from dissociation of water and perhaps linked to dissolution of the host mineral matrix (Fig. 1c).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    Neither investigation detected the strong Raman peak of hematite at ~1310 cm-1 peak or the ordered-disordered carbon bands of MMC (~1350 and ~1600 cm-1).

    “Therefore neither investigation detected the strong Raman peak of hematite at ~1310 cm -1 peak or the ordered-disordered carbon bands of MMC (~1350 and ~1600 cm -1 ).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Interpretationnone given

    There is currently no satisfactory explanation for this variation.

    “There is currently no satisfactory explanation for this variation.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Similar interaction between CO2 and FeO have also been proposed as being responsible for MMC reservoirs in meteorites and IDPs.

    “Similar interaction between CO 2 and FeO have also been proposed as being responsible for MMC reservoirs in meteorites and IDPs”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Allamandola et al. 1988
    • cites Anders 1991 source
    • cites Nakamura et al. 2002

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    One event, known as the I3 shock event, would have produced a heat pulse between 200 and 450 °C with pressures of up to 50 GPa, which should decompose siderite to magnetite and CO2, as well as produce the observed PAHs.

    “One event, known as the I3 shock event, would have produced a heat pulse between 200 and 450 °C with pressures of up to 50 GPa, which should decompose siderite to magnetite and CO 2 , as well as produce the observed PAHs (Treiman 2003).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Treiman 2003 source

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductown data

    Before analysis, our experimental null hypothesis stated that all the features seen in AHL 84001 have an abiogenic origin. Based on our current research, this hypothesis could not be falsified.

    “Before analysis, our experimental null hypothesis stated that all the features seen in AHL 84001 have an abiogenic origin.Based on our current research, this hypothesis could not be falsified.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    Both populations probably formed from rapid cooling of fluids, although mantle-derived fluids would probably have a much higher initial temperature than those formed from meteoric fluids.

    “Both, however, probably formed from rapid cooling of fluids, although mantle-derived fluids would probably have a much higher initial temperature than those formed from meteoric fluids.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    Two types of carbonate globules have previously been described in ALH 84001: dark brown globules containing a single magnetite rim, and lighter orange-colored globules with a second magnetite outer rim bounded by an area of magnesite.

    “Two types of carbonate globules (Fig. 1) have previously been described in ALH 84001: dark brown globules containing a single magnetite rim, and lighter orange-colored globules with a second magnetite outer rim bounded by an area of magnesite (e.g., Figs.1a and 1d) (McKay et al. 1996;Treiman et al. 2003).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites McKay et al. 1996 source
    • cites Treiman et al. 2003

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    The temperatures at which the ALH 84001 globules formed cannot be constrained.

    “Although we cannot constrain the temperatures at which this occurred”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    This study shows unequivocally, and for the first time, the existence of an abiotic MMC synthesis mechanism that is indigenous to Mars.

    “This study shows unequivocally, and for the first time, the existence of an abiotic MMC synthesis mechanism that is indigenous to Mars”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    Both depositional and impact-induced conditions in ALH 84001 could have formed MMC.

    “Both depositional and impact-induced conditions in ALH 84001 could have formed MMC”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationown data

    An impact shock formation mechanism for the hematite from siderite cannot be ruled out.

    “We cannot rule out an impact shock formation mechanism for the hematite from siderite”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationnone given

    Evidence of globule decarbonation and the presence of magnetite and MMC phases in the matrix of the rock may be linked.

    “We tentatively suggest that evidence of globule decarbonation and the presence of magnetite and MMC phases in the matrix of the rock may be linked.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationnone given

    The outer orange layers of the carbonate may incorporate changes due to terrestrial alteration and be the repository for the organic contamination known to exist in this meteorite.

    “The outer orange layers of the carbonate may incorporate changes due to terrestrial alteration and be the repository for the organic contamination known to exist in this meteorite.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S1 (asserted).

    Interpretationreasoning

    The ALH 84001 globules formed in a similar manner to the BVC globules, i.e., by cooling of hydrothermal fluids.

    “Due to the similarity of the BVC and ALH 84001 globules, we hypothesize that the ALH 84001 globules formed in a similar manner, i.e., by cooling of hydrothermal fluids.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The BVC carbonate globules formed by cooling of hydrothermal fluids.
60 of 60

  • The paper relies on this without support.

    The MMC measured in ALH 84001 is indigenous to the meteorite and not terrestrial contamination.

    “Macromolecular carbon (MMC) was found in intimate association with magnetite in both ALH 84001 and BVC carbonates.”

  • The authors state this as an assumption.

    The system was buffered by hematite and magnetite as temperature decreased.

    “This is not an unreasonable assumption given the presence of both hematite and magnetite in BVC and ALH 84001 (Koziol 2004).”

  • The paper relies on this without support.

    The BVC carbonate globules formed by cooling of hydrothermal fluids.

    “we hypothesize that the ALH 84001 globules formed in a similar manner, i.e., by cooling of hydrothermal fluids.”
3 of 3

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Figure 6a is assigned to two different samples

    Minor

    The results identify the trio of globules in Figure 6a as sample ALH 84001-357, but the figure caption identifies it as ALH 84001-380.

  • Figure 3a has conflicting carbonate peak assignments

    Minor

    The results describe Figure 3a as a carbonate intensity map at approximately 1090 cm−1, while its caption assigns the mapped carbonate peak to approximately 330 cm−1.

2 of 2

Cites

Flagged first, then by citations

Research works printed but not linked: 22

  1. Barber D. J., 2001, Transmission electron microscopy of carbonates and associated minerals in ALH 84001; Impact‐induced deformation and carbonate decomposition (abstract), Meteoritics & Planetary Science, 36, A13
  2. Bell M. S., 1999, Analysis of carbonates in ALH 84001 Martian meteorite by Raman spectroscopy, GSA Abstracts with Programs, 31, 45
  3. Bell M. S., 2000, Alteration of an ALH 84001 analog carbonate to magnetite by shock metamorphism, GSA Abstracts with Programs, 32, 240
  4. ClemettS. J. DulayM. T. GilletteS. ChillierX. D. F. MahajanT. B. andZareR. N.1998.Are the polycyclic aromatic hydrocarbons in ALH 84001 of extraterrestrial origin? A reevaluation(abstract #1812). 29th Lunar and Planetary Science Conference. CD‐ROM.
  5. EilerJ. M. ValleyJ. W. GrahamC. M. andBlackD.1997a.Standardization of SIMS analysis of O and C isotope ratios in carbonates from ALH 84001 (abstract). 28th Lunar and Planetary Science Conference. pp.327–328.
  6. Eiler J. M., 1997, Stable isotopes in Allan Hills 84001: An ion microprobe study (abstract), Meteoritics & Planetary Science, 32, A46
  7. Eiler J. M., 1998, Geochemistry of carbonates and glass in Allan Hills 84001 (abstract), Meteoritics & Planetary Science, 33, A44
  8. Flynn G. J., 1998, Carbon in Allan Hills 84001 carbonate and rim (abstract), Meteoritics & Planetary Science, 33, A50
  9. FlynnG. J. KellerL. P. KirzJ. WirickS. BajtS. ChapmanH. N. andBlackD.1997.Carbon mapping and carbon‐XANES measurements on carbonate globules from ALH 84001 (abstract). 28th Lunar and Planetary Science Conference. pp.365–366.
  10. GoldenD. C. MingD. W. LauerH. V. Jr. andMorrisR. V.2004a.Thermal decomposition of siderite‐pyrite assemblages: Implications for sulfide mineralogy in Martian meteorite ALH 84001 carbonate globules(abstract #1396). 35th Lunar and Planetary Science Conference. CD‐ROM.
  11. KoziolA. M.2000.Carbonate and magnetite parageneses as monitors of carbon dioxide and oxygen fugacity(abstract #1424). 31st Lunar and Planetary Science Conference. CD‐ROM.
  12. Koziol A. M., 2001, A siderite‐magnesite decarbonation study, GSA Abstracts with Programs, 33, 311
  13. MittlefehldtD. W.1994a.ALH 84001 cumulate orthopyroxenite: A previously unappreciated Martian meteorite (abstract). 20th Lunar and Planetary Science Conference. pp.911–912.
  14. MojzsisS. J. CoathC. D. BunchT. BlakeD. TreimanA. H. andAmundsenH. E. F.1999.Carbonate “rosettes” in xenoliths from Spitzbergen: SIMS analysis of O and C isotope ratios in a potential terrestrial analogue to Martian meteorite ALH 84001(abstract #2032). 30th Lunar and Planetary Science Conference. CD‐ROM.
  15. Nakamura K., 2002, Raman spectroscopy of carbonaceous globules in the Tagish Lake chondrite, Meteoritics & Planetary Science, 37, A107
  16. NilesP. B. LeshinL. A. SockiR. A. GuanY. GoldenD. C. MingD. W. andGibsonE. K.2004a.Chemical and isotopic study of lab‐formed carbonates under cryogenic and hydrothermal conditions(abstract #8043). Second Conference on Early Mars: Geologic Hydrologic and Climatic Evolution and the Implications for Life. CD‐ROM.
  17. NilesP. B. LeshinL. A. SockiR. A. GuanY. MingD. W. andGibsonE. K.2004b.Cryogenic calcite—A morphologic and isotopic analog to the ALH 84001 carbonates(abstract #1459). 35th Lunar and Planetary Science Conference.
  18. NilesP. B. ZolotovM. Y. andLeshinL. A.2006.The role of CO2in aqueous alteration of ultra‐mafic rocks and the formation of Mg‐ Fe‐rich aqueous solutions on early Mars(abstract #1440). 37th Lunar and Planetary Science Conference. CD‐ROM.
  19. ScottE. R. D. YamaguchiA. KrotA. N. BlackD. andBlanchardD.1997b.Shock melting of carbonate plagioclase and silica in the Martian meteorite ALH 84001. 28th Lunar and Planetary Science Conference. pp.1271–1272.
  20. Scott E. R. D., 2002, Origin of magnetite in Martian meteorite Allan Hills 84001 (abstract), Meteoritics & Planetary Science, 37, A128
  21. SteeleA. AmundsenH. E. F. FriesM. VicenziE. P. BenningL. MauleJ. MysenB. ToporskiJ. SchweizerM. andFogelM.2005.A morphological and chemical study of carbonate globules contained within mantle xenoliths of the Sverrefjell volcano Spitsbergen—Implications for ALH 84001(abstract #2173). 36th Lunar and Planetary Science Conference. CD‐ROM.
  22. ValleyJ. W. EilerJ. M. GrahamC. M. GibsonE. K. Jr. RomanekC. S. BlackD. andBlanchardD.1997a.Ion microprobe analysis of oxygen and carbon isotope ratios in the ALH 84001 (abstract). 28th Lunar and Planetary Science Conference. pp1475–1476.

Cited by

Sorted by citations

Related

Authors
Steele, A., Fries, M. D., Amundsen, H. E. F., Mysen, B. O., Fogel, M. L., Schweizer, M., & Boctor, N. Z.
Affiliations
  • Carnegie Institution for Science (US)
  • University of Oslo (NO)
Corresponding author
Steele, A.
ORCID
Venue
Meteoritics & Planetary Science
Publisher
Wiley
Published
2007-09
Volume
42
Issue
9
Pages
1549-1566
ISSN
  • 1086-9379 (ISSN-L)
  • 1945-5100
DOI
10.1111/j.1945-5100.2007.tb00590.x
OpenAlex
W2095154141
Cited by
117
References
54
Citations by year
2026: 10 · 2025: 6 · 2024: 4 · 2023: 6 · 2022: 6 · 2021: 10 · 2020: 6 · 2018: 11 · 2017: 7 · 2016: 4 · 2015: 2 · 2014: 8 · 2013: 8 · 2012: 12
FWCI
2.79
Type
journal article
Language
en
Open access
Licence
onlinelibrary.wiley.com/termsAndConditions#vor (vor, 878 d)
Locations
  • Meteoritics and Planetary Science (publishedVersion)
  • UA Campus Repository (The University of Arizona) (acceptedVersion)
Funders
  • National Aeronautics and Space Administration
  • University of Oxford
  • Universitetet i Oslo
  • Norsk Polarinstitutt
  • NASA Astrobiology Institute
Topics
  • Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Planetary Science and Exploration
  • Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Astro and Planetary Science
  • Physical Sciences › Earth and Planetary Sciences › Geophysics › Geological and Geochemical Analysis
Keywords
ALH84001, Martian meteorites, carbonate globules, hematite, magnetite, magnesite, oxygen isotopes, hydrothermal alteration, mantle peridotite xenoliths, terrestrial analogs, globule formation

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-11.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-11.

Cited sources are checked by gpt-6-sol.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review